-12.5% is the change from 800 to 700
Calculation steps:
[( 700 - 800 ) ÷ 800] x 100 = -12.5%
Formula
Percentage change = [(700 - 800) / 800] x 100
Subtract the new number by the original number
700 - 800 = -100
-100 ÷ 800 = -0.125
-0.125 x 100 = -12.5%